Thermochemical reactor systems typically employ solar energy to help drive endothermic chemical reactions at elevated temperatures. Such reactions may include production of fuels or fuel precursors; e.g. splitting water or carbon dioxide or upgrading of hydrocarbons, or the like. However, existing systems that use solar energy to drive endothermic reactions tend to suffer from drawbacks including being inefficient, being complex to build or operate, having short operational lifespan, etc.